Potential of Equisetum ramosissimum Desf. for remediation of antimony flotation tailings: a case study.

A flooding event caused collapsing of the Stolice flotation tailing dam and spilling of large volumes of sludge into environment. Urgent remediation measures have not been applied due to the lack of financial resources. Remediation values for Sb, Zn, and Pb in the flotation tailing samples were exceeded 20.5, 4.2, and 1.15 times, respectively, emphasizing the need for remediation. Plants growing on mine spoils represent useful tools for environmental monitoring and soil remediation. The appearance of Equisetum ramosissimum as a dominant colonizer on the flotation tailings indicates that biological reclamation of the site is possible. Equisetum ramosissimum shows the ability to phytostabilize and immobilize available fractions of Fe, Mn, Zn, Pb, and Sb. Transfer rate of metals from roots to shoots reveals exclusion of elements from the shoots, preventing their further spreading through the food chain. The results of this study show that E. ramosissimum can be an additional tool for environmental monitoring and remediation of flotation tailings after hazardous events.

Metal accumulation in populations of Calamagrostis epigejos (L.) Roth from diverse anthropogenically degraded sites (SE Europe, Serbia).

Heavy metal accumulation is recognized as a very important global pollution problem in the last decades. Plant species have been recognized as natural bioindicators of environmental pollution, especially the amount of heavy metals in soils. Moreover, only a limited number of plant species can survive in highly contaminated soils. It is also known that metal accumulation can vary greatly among different populations of the same species. This study examines the chemical composition and accumulation potential of the expansive clonal grass Calamagrostis epigejos at five localities exposed to different levels of anthropogenic pressure. Considerable differences were observed between uptake, translocation, and accumulation of total and available heavy metals, such differences corresponding to soil physico-chemical characteristics and the level of site pollution. The results indicate that Calamagrostis epigejos uptakes a significant portion of the available fraction of heavy metals in the soil and stores it in the roots, thereby exhibiting a certain potential for metal phytostabilization.

Relation between edaphic factors and vegetation development on copper mine wastes: a case study from Bor (Serbia, SE Europe).

The relationship between edaphic characteristics and vegetation growing on mine wastes in the Bor region (East Serbia, SE Europe) was studied using multivariate statistical analysis. The influence of edaphic factors on the composition of plant life-forms was also investigated, since it could reflect strategies for the avoidance of or tolerance to disturbances of ecosystems. The goal was to provide potential models for the restoration and management of this and similar mine waste areas. The results of this study imply that soil textures, nitrogen contents, reclamation technology and the presence of hydrothermally altered andesite as the type of bedrock significantly influenced plant colonization and vegetation composition of the Bor mine wastes. These edaphic factors explained 30.3 % of the total variation in the vegetation data set. It was also revealed that the pattern of plant life-forms found on the considered site groups corresponded to the soil texture. Based on their relative abundance on the investigated sites and relationships with soil properties it is concluded that therophytes and geophytes are unsuccessful primary colonizers of the Bor mine wastes. Hemicryptophytes of psammophytic character were the most successful primary colonizers and therefore potential candidates for anthropogenically-assisted natural recovery. This study suggested that an assessment of edaphic factors should be widely used in the characterization of mine wastes prior to reclamation. Estimation of their role in the development of existing mine vegetation should predate reclamation procedures. Thus, approaches based on adequate plant life-forms should have a more prominent role in future mine reclamation schemes.

Recognising the role of ruderal species in restoration of degraded lands.

Ruderal plants are an important component of plant communities that develop on the range of anthropogenically degraded lands. Yet they were highly neglected and not recognised as desirable for restoration purposes. The aim of this study was to analyse the potential for using ruderal species in restoration processes and to identify preliminary criteria for species selection that could be included in ecological restoration of degraded man-made habitats under future conditions of increased human disturbance and climate changes. The desirable characteristics of the species depend primarily on the type of habitat to be restored, with plant height, specific leaf area, rooting depth and seed characteristics being the most important traits. The recognised ecosystem services of the species analysed show that the provisioning and regulating services are well represented, particularly erosion control, pollination, phytoremediation and other soil quality improvements. Most of the dominant and diagnostic ruderal species from the man-made habitats of the north-western Balkan Peninsula are sensitive to climate change and their potential distribution range is expected to decrease at the European scale. Higher certain ecological indicator values, as well as values for disturbance severity, frequency and soil disturbance indices were found for species that are expected to increase their range. Ruderal species are becoming increasingly important for restoration purposes, as the focus shifts to the significance of early successional species. The inclusion of ruderal species in the restoration of degraded sites should be based on criteria such as: non-invasiveness, plant traits favourable for colonisation (height, SLA, seed traits, rooting depth), values of ecological and disturbance indices, provision of ecosystem services, and change of distribution range under changing climate conditions.

Concentration and mobility of trace elements (Li, Ba, Sr, Ag, Hg, B) and macronutrients (Ca, Mg, K) in soil-orchid system on different bedrock types.

The mobility of chemical elements in the soil-orchid system has been poorly studied. The aim of this study is to evaluate the uptake and mobility of several trace (Li, Ba, Sr, Ag, Hg, and B) and macronutrients (Ca, Mg, and K) in the orchid Anacamptis morio (L.) R.M.Bateman, Pridgeon & M.W.Chase from soils in western Serbia. The sampling sites are characterized by three different bedrock types-cherts, limestones, and serpentines, which are the source of the significant chemical differences in the elemental status of the soil and plant tissues. The four-step Community Bureau of Reference sequential extraction procedure was used to determine the distribution of fractions and predict their potential phytoavailability. The orchid and soil samples were analyzed for total elemental content analysis using ICP-OES. The greatest potential for plant availability was determined for Ba and Sr, representing about 80% of the total soil content. More than 40% of Li in the soils was found to be potentially phytoavailable. Significant correlations were found between the total content of Li, B, and Sr in soils. Between 38 and 60% of Li content and more than 80% of Ba and Sr content were determined to be potentially phytoavailable by sequential analysis. The highest bioconcentration factor (> 1) was determined in the case of B and Sr for all orchid organs, while translocation factor for Li was highest in tubers and leaves. The studied elements were mainly stored in tubers and roots, indicating the exclusion strategy of A. morio as a metal tolerance mechanism. The data obtained showed significant differences in metal content in soils and plants originating from sites with different parent materials, suggesting that bedrock type and associated soil properties are important factors that determine chemical element mobility and uptake.

Spatial distribution and source identification of heavy metals in European mountain beech forests soils.

The main objectives of this research were to (i) investigate the concentration; (ii) characterize the distribution; (iii) determine the sources apportionment; (iv) estimate environmental and health risks of heavy metals in soil from mountain beech forest. A total of 76 soil samples from 20 pure beech forest stands from Bosnia and Herzegovina (BA), Bulgaria (BG), Check Republic (CZ), Germany (DE), Italy (IT), Poland (PL), Romania (RO), Serbia (RS), Slovakia (SK), Slovenia (SL), and Spain (ES) were collected. The content of major elements was measured by X-ray fluorescence spectroscopy (XRF). The content of heavy metals was measured by inductively coupled plasma-optical emission spectrometry (ICP/OES). Heavy metals had a specific concentration range, which followed in soil samples from depth 0-40 cm the common order (low to high): Hg < Cd < As < Co < Pb < Ni < Cu < Cr < Zn, and from depth 40-80 cm: Hg < Cd < As < Pb < Co < Ni < Cu < Cr < Zn. The grouping of the examined parameters according to rock types, soil types, and localities indicated the separation of carbonate rocks from other substrates, luvisol, and rendzina from other soil types, and samples from BA, SL, and IT from other localities. According to sources apportionment As, Pb and Zn are of anthropogenic origin, Cd, Co, Cr, and Ni are of geogenic origin, while the middle position of Cu and Hg indicates a combined contribution of both sources. Elements Cd and Hg indicated severe to extremely severe enrichment with a mean value of 24.3 and 70.6, respectively. Based on the determined values Ni, Cr, As and Cd do not pose a health risk.

Brassica Species in Phytoextractions: Real Potentials and Challenges.

The genus Brassica is recognized for including species with phytoaccumulation potential and a large amount of research has been carried out in this area under a variety of conditions, from laboratory experiments to field trials, with spiked or naturally contaminated soils, using one- or multi-element contaminated soil, generating various and sometimes contradictory results with limited practical applications. To date, the actual field potential of Brassica species and the feasibility of a complete phytoextraction process have not been fully evaluated. Therefore, the aim of this study was to summarize the results of the experiments that have been performed with a view to analyzing real potentials and limitations. The reduced biomass and low metal mobility in the soil have been addressed by the development of chemically or biologically assisted phytoremediation technologies, the use of soil amendments, and the application of crop management strategies. Certain issues, such as the fate of harvested biomass or the performance of species in multi-metal-contaminated soils, remain to be solved by future research. Potential improvements to current experimental settings include testing species grown to full maturity, using a greater amount of soil in experiments, conducting more trials under real field conditions, developing improved crop management systems, and optimizing solutions for harvested biomass disposal.

Accumulation of trace elements in Tussilago farfara colonizing post-flotation tailing sites in Serbia.

The purpose of this study was to examine the accumulation potential of spontaneously developed Tussilago farfara populations colonizing sites with different levels of anthropogenic pollution. Physical characteristics of the soil are presented, together with the concentrations of macroelements and microelements (Ca, Mg, Fe, S, Al, Pb, Zn, Cu, Cd, Mn, As, Sb, Ag, Ti, and Sr) in both soil and plants. The biological concentration, accumulation, and translocation factors were used to assess the potential for heavy metal accumulation. Considerable differences were found among assessions from unevenly contaminated habitats, particularly in comparison with an unpolluted site. In line with the ore's characteristics, substrate samples from polluted sites were heavily contaminated with Pb, Zn, As, and Sb. Increased levels of microelements were also detected in plant samples from flotation tailings. Despite active absorption of Zn, Cu, Cd, Mn, and Sr by the plants from mining sites, the detected quantities of these elements in all samples were below the hyperaccumulation threshold. However, the obtained results indicate that the use of T. farfara from such sites in traditional medicine could pose a risk to human health due to accumulation of several toxic elements in the plant's aboveground tissues. Additionally, as a successful primary colonizer and stabilizer of technogenic substrates, T. farfara has an important role in the initial phases of revegetation of highly contaminated sites.

Geochemical distribution of selected elements in flotation tailings and soils/sediments from the dam spill at the abandoned antimony mine Stolice, Serbia.

Materials held within mine tailings pose a serious risk to the environment in cases of tailings dam failure. Collapse of the tailing dam at the Stolice antimony mine in West Serbia caused a spilling of tailing slurry into the nearby river watersheds. Medium-term effects of As, Pb, Sb, Zn, and Cd from the tailings material that remained in the flooded zone 3 years after the initial exposure were evaluated. Mobility of these elements was determined by analyzing their distribution between exchangeable, reducible, oxidizable, and residual phases. Results indicate that Fe-Mn oxides represent important sinks for As, Cd, Pb, and Sb. Multivariate statistical analysis revealed that concentrations of the analyzed elements were related to sand-sized fractions, as they tended to adsorb or co-precipitate as coatings on larger particles (particularly feldspar and quartz) upon the change of redox conditions. Assessment of the most relevant physico-chemical factors, metal(loid) concentration, and mobility can be used as tool to characterize the degree of contamination of impacted sites. Percentage of sand-sized particles, content of investigated metal(loid)s, and their amount in the reducible fractions are factors determining the best remediation techniques for the area impacted by tailing spill.